Heat exchangers of a design having a plurality of flat tubes, fins which are joined to the plurality of flat tubes, and header collecting tubes which are coupled respectively to the plurality of flat tubes at a one end side and another end side thereof, for bringing about heat exchange between a refrigerant flowing through the interior the flat tubes and air flowing to the outside of the flat tubes, are known in the prior art.
For example, the heat exchanger disclosed in Japanese Laid-open Patent No. 2-219966 is configured such that a plurality of outflow tubes extending in a horizontal direction are connected at either end to header collecting tubes that respectively extend in a vertical direction.
The heat exchanger disclosed in Japanese Laid-open Patent No. 2-219966 is directed to the problem that, in the interior of the header collecting tubes that extend in the vertical direction, liquid phase refrigerant of high specific gravity collects towards the bottom while gas phase refrigerant of low specific gravity collects towards the top, thereby giving rise to eccentric flow; in order to solve this problem, the feature of forming a throttle inside the header collecting tubes is proposed.
Passing the refrigerant through the throttle formed in this manner facilitates mixing of the gas phase refrigerant and the liquid phase refrigerant, while at the same time improves the flow velocity, making it easy for the refrigerant to reach the top within the header collecting tubes, thereby minimizing eccentric flow of the refrigerant.